1. Field of the Invention
The present invention relates to control of static electricity in the air, and more particularly to an ionizing apparatus and a discharge electrode bar for the same.
2. Description of the Related Art
Elimination of static electricity (diselectrification) is used for the control of the static electricity in the air, such as purification in a clean room, prevention of electrification of floating particles, etc. A number of ionizing apparatuses of a corona discharge type have been used for non-contact diselectrification.
FIGS. 6 and 7 show a discharge electrode bar included in a DC ionizing apparatus which is currently available. The discharge electrode bar 1 includes an elongated cylindrical case 2. This case 2 has a plurality of discharge electrodes 3 (FIG. 6) arranged in a mutually spaced relation in a longitudinal direction. The case 2 contains a high voltage power supply unit 4 and a control unit 5 which are positioned between the adjacent pairs of discharge electrodes 3, 3. Moreover, the case 2 of the discharge electrode bar 1 is divided into two sections, namely an upper divisional case section 7 and a lower divisional case section 8 (FIG. 7).
It is to be noted that the plurality of the discharge electrodes 3 include positive poles and negative poles which are identified in the drawing with reference numerals 3a and 3b respectively. A flexible tube 6 is arranged inside case 2 so as to supply air to areas surrounding the discharge electrodes 3.
In the discharge electrode bar 1 of the related art, a structure has been employed where the high voltage power supply unit 4 and the control unit 5 are positioned between the adjacent discharge electrodes 3, 3. Therefore, the discharge electrode bar in the related art has had a problem that a minimum design distance between the adjacent discharge electrodes 3, 3 has been restricted by the size of the high voltage power supply unit 4 or the control unit 5. This creates a problem in cases where the discharge electrode bar 1 is intended to be arranged near a work site; for example, the diselectrification effects may lack uniformity.
In order to assemble the discharge electrode bar 1, the high voltage power supply unit 4, or the control unit 5, must first be fixed to the lower divisional case section 8 which has a large depth dimension. Inserting the high voltage power supply unit 4 or the control unit 5 into the lower divisional case section 8 and fixing them had to be performed through a narrow opening 8a of the lower divisional case section 8. Accordingly, in many cases, the opening 8a of the lower divisional case section 8 must be widened forcibly to accommodate the above-mentioned components, which makes assembly difficult.
In view of the above, an object of the invention is to provide an ionizing apparatus and a discharge electrode bar for the same in which flexibility of setting the distance between the discharge electrodes of the discharge electrode bar can be enhanced.
A further object of the invention is to provide an ionizing apparatus and a discharge electrode bar for the same in which the ease of assembling the components of the discharge electrode bar can be improved.
Another object of the invention is to provide a discharge electrode bar which will disturb air currents of the atmosphere to a minimum degree.
The above-described technical problems can be solved by an ionizing apparatus comprising a discharge electrode bar which includes an elongated case, a plurality of discharge electrodes arranged in a mutually spaced relation in a longitudinal direction of the case, a high voltage power supply unit and a control unit. In the ionizing apparatus, the high voltage power supply and the control unit are arranged in a line in the longitudinal direction of the case in an upper region of the case where they do not interfere with the discharge electrodes.
According to another aspect of the invention, the above-described technical problems can be solved by a discharge electrode bar for an ionizing apparatus comprising: an elongated case, a high voltage power supply unit and a control unit which are arranged in a line in a longitudinal direction of the case in an upper region of the case, an elongated air unit disposed in a lower region of the case, a plurality of discharge electrodes detachably fitted to the air unit and arranged in a mutually spaced relation in a longitudinal direction of the air unit, and an independent air passage which is isolated from the atmosphere inside the case and adapted to discharge air supplied from an air source through areas surrounding the discharge electrodes. In the discharge electrode bar, a part of the independent air passage is formed of an air passage in the air unit, and the air supplied to the air passage in the air unit is discharged to the exterior from the areas surrounding the discharge electrodes.
In a preferred embodiment according to the invention, the aforesaid case has a base plate portion which substantially separates an interior of the case into an upper part and a lower part. Because the interior of the case is substantially divided into an upper space and a lower space by the base plate, and the high voltage power supply unit which generates heat is disposed in the upper space, even if protecting material or filling material in the case, for example, becomes gasified, the gas will be prevented from flowing into the lower space. Preferably, the high voltage power supply unit may be hermetically sealed inside an airtight box. The high voltage power supply unit may be covered with a silicone resin or epoxy resin as the protecting material, if used. The silicone resin or epoxy resin can be hermetically sealed in the airtight box together with the high voltage power supply unit.
Left and right divisional case sections constituting the case may preferably form an inverted U-shape when they have been assembled into one piece. This shape may restrain turbulence in the air current flowing in a lower area of the atmosphere around the discharge electrode bar.
Further, the air unit may be preferably provided with projections on its side walls, and the left and right divisional case sections may be preferably provided with grooves for receiving the projections of the air unit on their inner walls. In this manner, in a state where the left and right divisional case sections are separated, the air unit can be incorporated into one of the divisional case sections by engaging the projection of the air unit in the groove of the one divisional case section and then, the other divisional case section can be assembled to the one divisional case section to form one piece, enabling the left and right divisional case sections to provide a configuration in which the air unit is held between them. The projection may be in a form of a ridge extending in a longitudinal direction of the air unit. Alternatively, the projections or ridges may be provided on the left and right divisional case sections, and the grooves for receiving them may be provided in the air unit.